GHSA-hrxh-6v49-42gf

ADVISORY - github

Summary

Multiple security vulnerabilities have been identified and addressed in grpc-go affecting the xDS RBAC authorization engine (internal/xds/rbac) and the HTTP/2 transport server implementation (internal/transport). These vulnerabilities could result in:

Authorization Bypass (Fail-Open) when translating xDS RBAC policies containing Metadata or RequestedServerName fields.
Denial of Service (High CPU Consumption) due to an HTTP/2 Rapid Reset mitigation bypass during client-initiated stream resets.
Denial of Service (Server Panic) when parsing crafted xDS RBAC policies containing NOT rules around unsupported fields.

Impact

What kind of vulnerability is it? Who is impacted?

xDS RBAC Authorization Bypass via `Metadata` & `RequestedServerName` matchers

Affected Component: xDS RBAC
Impact: When building policy matchers for gRPC RBAC from xDS configurations, unsupported permission and principal rules (specifically Metadata and RequestedServerName) were silently ignored and treated as no-ops.
- If an authorization policy relied purely on these matchers for access control, treating those rules as no-ops effectively removed the restrictions.
If these unsupported rules were nested inside logical NOT rules (Permission_NotRule / Principal_NotId) or multi-condition OR/AND rules, silently dropping them changed the boolean logic flow of the authorization engine.

As a result, policy evaluation decisions could fail open, allowing unauthorized clients to access protected gRPC services or resources.

HTTP/2 Rapid Reset Mitigation Bypass / Denial of Service via Stream Aborts

Affected Component: HTTP/2 transport
Impact: Earlier mitigations in grpc-go for HTTP/2 Rapid Reset only applied threshold checks to items that directly resulted in control frames being written back to the wire, such as SETTINGS ACKs or server-initiated RST_STREAMs.

When a client initiated a rapid flood of stream creation (HEADERS) immediately followed by stream termination RST_STREAM, items queued up in the control buffer without counting against the transport response frame threshold. An attacker can repeatedly trigger this flood sequence to bypass reader blocking, resulting in high CPU usage, and Denial of Service (DoS).

Denial of Service (Panic) in xDS RBAC Engine via Unsupported Fields inside NOT Rules

Affected Component: xDS RBAC
Impact: The xDS RBAC policy translators recursively generate matchers for nested rules. When a NOT rule wrapped an unsupported or unhandled field (such as SourcedMetadata), the recursive step returned an empty matcher. This could result in a runtime panic when the RBAC engine attempts to authorize an incoming request.

An attacker or misconfigured/malicious xDS management server delivering an LDS/RDS update containing a NOT rule around an unhandled field causes the gRPC server process to crash immediately (CWE-248 / Denial of Service).

Patches

Has the problem been patched? What versions should users upgrade to?

All three issues have been fixed in master and will be released in 1.82.1 shortly.

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

If upgrading grpc-go immediately is not possible, apply the following workarounds based on your deployment architecture:

For xDS RBAC Vulnerabilities & Panics: Ensure that upstream xDS management servers do not push RBAC policies containing Metadata, RequestedServerName, or NOT rules wrapping unsupported fields (such as SourcedMetadata) to grpc-go servers.
For HTTP/2 Rapid Reset DOS: Configure upstream reverse proxies or load balancers (such as Envoy) with strict HTTP/2 max_concurrent_streams limits and active rate limiting on RST_STREAM frequency per connection.

Severity

Vulnerability	Qualitative Severity	Approximate CVSS v3.1 Score	Primary Impact
xDS RBAC Authorization Bypass	High	`8.2`	Unauthorized Access / Fail-Open
HTTP/2 Rapid Reset DOS Bypass	High	`7.5`	High CPU Consumption / Denial of Service
xDS RBAC Engine Server Panic	Medium	`5.9`	Process Crash / Denial of Service

Common Weakness Enumeration (CWE)

ADVISORY - github

CWE-248⁠

Uncaught Exception

CWE-770⁠

Allocation of Resources Without Limits or Throttling

CWE-863⁠

Incorrect Authorization

Impacted images

Advisories

GitHub

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY IDGHSA-hrxh-6v49-42gf⁠

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)

CWE-248⁠CWE-770⁠CWE-863⁠

CVSS SCORE

8.8high

Package	Type	OS Name	OS Version	Affected Ranges	Fix Versions
google.golang.org/grpc	golang	-	-	<1.82.1	1.82.1

CVSS:4 Severity and metrics

The CVSS metrics represent different qualitative aspects of a vulnerability that impact the overall score, as defined by the CVSS Specification⁠.

The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone). One example of an Adjacent attack would be an ARP (IPv4) or neighbor discovery (IPv6) flood leading to a denial of service on the local LAN segment (e.g., CVE-2013-6014).

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.

The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.

The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.

The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges.

There is no loss of confidentiality within the Vulnerable System.

There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the Vulnerable System. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the Vulnerable System.

There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the Vulnerable System; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the Vulnerable System (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

CREATED

2 months ago

UPDATED

2 months ago

ADVISORY ID

MINI-xxjr-p3g5-9g3c

EXPLOITABILITY SCORE

EXPLOITS FOUND

COMMON WEAKNESS ENUMERATION (CWE)-

RATING UNAVAILABLE FROM ADVISORY

GHSA-hrxh-6v49-42gf

Summary

Impact

xDS RBAC Authorization Bypass via Metadata & RequestedServerName matchers

HTTP/2 Rapid Reset Mitigation Bypass / Denial of Service via Stream Aborts

Denial of Service (Panic) in xDS RBAC Engine via Unsupported Fields inside NOT Rules

Patches

Workarounds

Severity

Common Weakness Enumeration (CWE)

CWE-248⁠

CWE-770⁠

CWE-863⁠

Advisories

GitHub

CVSS SCORE

Attack Vector (AV)Network

Attack Complexity (AC)Low

Attack Requirements (AT)None

Privileges Required (PR)None

User Interaction (UI)None

Confidentiality Impact to the Vulnerable System (VC)None

Confidentiality Impact to the Subsequent System (SC)None

Integrity Impact to the Vulnerable System (VI)High

Integrity Impact to the Subsequent System (SI)None

Vulnerable System Availability Impact (VA)High

Subsequent System Availability Impact (SA)None

GoLang

Chainguard

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xDS RBAC Authorization Bypass via `Metadata` & `RequestedServerName` matchers